U.S. patent number 6,268,784 [Application Number 09/341,628] was granted by the patent office on 2001-07-31 for magnetic valve.
This patent grant is currently assigned to Continental Teves AG & Co., oHG. Invention is credited to Hans-Jorg Feigel, Michael Germuth-Loffler, Manfred Ruffer, Wolfgang Schieblich.
United States Patent |
6,268,784 |
Feigel , et al. |
July 31, 2001 |
Magnetic valve
Abstract
The present invention discloses a magnetic valve for liquid and
gaseous working media, in particular for hydraulic brake systems in
automotive vehicles, which includes a first cylindrical housing
part that is encompassed on its outside by a magnetic coil and has
a cylindrical recess inside which extends in an axial direction to
accommodate and guide an axmature, a tappet which is displaceable
by the armature in an axial direction in opposition to a resetting
spring, a second cylindrical housing part which is arranged
coaxially to the first housing part and includes a cylindrical
recess extending in an axial direction, the said recess being in
connection to outside valve ports and in which a valve seat
cooperating with the tappet is arranged. According to the present
invention, the first and second housing parts form a housing which
is made in one piece of a ferromagnetic material and encompasses
the armature over at least part of its longitudinal extension in
the shape of a sleeve whose walls are sufficiently thick to reduce
the magnetic short-circuit but are not thicker than required to
reliably accommodate mechanical stresses.
Inventors: |
Feigel; Hans-Jorg (Rosbach,
DE), Ruffer; Manfred (Sulzbach, DE),
Germuth-Loffler; Michael (Kleinwallstadt, DE),
Schieblich; Wolfgang (Weiterstadt, DE) |
Assignee: |
Continental Teves AG & Co.,
oHG (Frankfurt, DE)
|
Family
ID: |
7817323 |
Appl.
No.: |
09/341,628 |
Filed: |
October 20, 1999 |
PCT
Filed: |
December 22, 1997 |
PCT No.: |
PCT/EP97/07239 |
371
Date: |
October 20, 1999 |
102(e)
Date: |
October 20, 1999 |
PCT
Pub. No.: |
WO98/31577 |
PCT
Pub. Date: |
July 23, 1998 |
Foreign Application Priority Data
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|
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Jan 14, 1997 [DE] |
|
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197 00 979 |
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Current U.S.
Class: |
335/261;
251/129.15; 335/278 |
Current CPC
Class: |
B60T
8/363 (20130101); B60T 15/027 (20130101); B60T
15/028 (20130101); H01F 7/081 (20130101); H01F
2007/1661 (20130101) |
Current International
Class: |
B60T
15/00 (20060101); B60T 15/02 (20060101); B60T
8/36 (20060101); H01F 7/08 (20060101); H01F
003/00 () |
Field of
Search: |
;333/256,251-9,276,261
;251/129.15-129.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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309 663 |
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Nov 1955 |
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CH |
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22 08 183 |
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Sep 1973 |
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DE |
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22 36 586 |
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Feb 1974 |
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DE |
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23 37 422 |
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Feb 1974 |
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DE |
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36 34 349 |
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May 1987 |
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DE |
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85 22 724 |
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Mar 1989 |
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DE |
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40 03 606 |
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Dec 1990 |
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DE |
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40 39 324 |
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Jun 1992 |
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DE |
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41 33 536 |
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Apr 1993 |
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DE |
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42 01 449 |
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Jul 1993 |
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DE |
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44 26 110 |
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Jan 1996 |
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DE |
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44 46 860 |
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Jul 1996 |
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DE |
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94 01 708 |
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Jan 1994 |
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WO |
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Other References
Search Report of the German Patent Office for Application No. 197
00 979 Jul. 1988..
|
Primary Examiner: Donovan; Lincoln
Attorney, Agent or Firm: Rader, Fishman & Grauer
PLLC
Claims
What is claimed is:
1. A magnetic valve for controlling movements of liquid and gaseous
working fluid contained therein, comprising:
a) a unitary housing of a ferromagnetic material, said housing
containing two axially extending and abutting compound interior
bores, the first bore having a first diameter, the second bore
having a second diameter larger than said first diameter;
b) said unitary housing including a first cylindrical housing part
that defines a first cylindrical sleeve, said first sleeve
containing said first bore;
c) a magnetic coil circumferentially disposed about said first
sleeve,
d) an axially moveable armature circumferentially supported within
said sleeve, and guided therein for reciprocal movement in response
to excitation via said magnetic coil,
e) said housing further comprising a second cylindrical housing
part coaxial with said first cylindrical housing part; said second
housing part defining a second cylindrical sleeve containing said
second bore, wherein the abutting interface of said first and
second bores defines an annular stop, wherein said stop faces the
interior of said second bore, and wherein said armature defines a
radially disposed end-face which becomes radially aligned with said
stop at one reciprocal limit of movement of said armature,
f) a tubular valve support disposed circumferentially within said
second bore and having one extremity thereof in contact with said
stop;
g) an annular tappet valve seat disposed fixedly within and at an
opposite extremity of said tubular valve support from said
stop,
h) a tappet valve defined by an axially moveable one-piece,
elongated pin body disposed within said valve support, said body
having a first diameter, and having an annular thrust portion
medially of its extremities, said thrust portion defining a boss
having radially disposed surfaces, said boss being of a second and
greater diameter than said first diameter of said body;
i) an annular washer support member positioned between said thrust
portion and said valve seat, said support member defining an
aperture, said pin body extending through, and being radially
supported by and moveable within the aperture of said washer;
and
j) a first resetting spring extending about one end of said tappet
pin body, said spring being supported on and between said annular
thrust portion of said pin body and said washer support member,
wherein one end of said one-piece pin body is disposed within said
tubular valve support for achieving direct physical contact with
the end-face of said armature.
2. Magnetic valve as claimed in claim 1, wherein an inside space of
the support member is subdivided by the valve seat, and one part of
the inside space is connected to a first outside valve port by way
of a radial bore and a second part of the inside space is connected
to a second outside valve port by way of an axial bore.
3. Magnetic valve as claimed in claim 1, wherein a bore for the
tappet includes an insert placed in the top of the support member
and a washer spaced axially with respect thereto, the insert being
fixed to the support member in an inside space above the valve seat
of the support member and aligned with the axis of the tappet,
wherein the insert and the washer each comprise axial passages to
convey fluid operating medium.
4. Magnetic valve as claimed in claim 3, including a second
resetting spring, wherein the tappet valve pin body in an area
between the insert and the washer includes a thrust defined by a
boss extending circumferentially about said pin body, said thrust
providing a radial support surface for one end of said second
resetting spring, said spring providing a force which acts in a
direction to open said magnetic valve, wherein said resetting
spring is supported at its other end by said washer.
5. Magnetic valve as claimed in claim 4, wherein interposed between
the armature and the first housing part is said first resetting
spring which acts in a direction to close the valve at a force
which is in excess of said force of the second resetting
spring.
6. Magnetic valve as claimed in claim 5, wherein interposed between
the armature and the first housing part is an anti-stick washer
having a thickness which is sized for establishing a limit of
movement of the armature in response to said excitation via said
magnetic coil.
7. Magnetic valve as claimed in claim 1, wherein said first
cylindrical housing part further defines a top housing part at its
uppermost extremity, and wherein a central axial bore is provided
in said top housing part, wherein a spherical ball is sized to
frictionally engage the top extremity of said central axial bore
for sealing said bore against leakage therefrom of said working
fluid, a cylinder defining a spacer between said first resetting
spring and said ball, whereby said ball is positioned axially
within said central axial bore for contacting and displacing said
cylinder, which contacts said first resetting spring, which
contacts said armature, which contacts said tappet, which contacts
said second resetting spring, in that order, for establishing
initial resetting spring adjustments of said valve.
8. Magnetic valve as claimed in claim 3 wherein said armature
further comprises a central guide pin comprising a first integral
boss at one end extending axially toward the first housing part,
and a plastically deformable bead comprising a second integral boss
at the opposite end, said second boss disposed for direct physical
contact with said tappet, said guide pin comprising means for
assuring concentricity of said first resetting spring, said
deformable bead comprising means for establishing resetting spring
adjustments of said valve.
9. Magnetic valve as claimed in claim 8 wherein the washer support
member further comprises an elongated annular bushing for imparting
support to that portion of the pin body of the tappet which extends
between said thrust portion and said valve seat.
Description
TECHNICAL FIELD
The present invention relates to a magnetic valve for liquid and
gaseous working media, in particular for hydraulic brake systems in
automotive vehicles.
BACKGROUND OF THE INVENTION
WO 94/01708 discloses a magnetic valve of this type. According to
the embodiment shown, the said valve comprises a top housing part
in the form of a thin-walled sleeve closed on its end and a bottom
housing part with valve seat and passages for the inflow and
outflow of a working medium. The bottom housing part is sealingly
pressed into a valve accommodation, and the top housing part is
encompassed by a magnetic coil. For connecting the two housing
parts, a magnetic core is used which is fitted with its bottom
cylindrical area into the bottom housing part and with its top
cylindrical area of smaller diameter is fitted into the top housing
part. The transition area has a conical design. The top housing
part with its conically enlarged bottom end abuts on the transition
area. The magnetic core and the top housing part are fastened above
the transition area in the bottom housing part by displacement of
plastic material. A tappet is guided in the magnetic core which
cooperates with the valve seat and is connected to a longitudinally
slidable armature that is arranged above the magnetic core in the
top housing part. The armature is urged against the stop formed by
the upper end of the top housing part by way of a resetting spring
which is supported in the magnetic core and acts in the opening
direction of the valve. When the magnetic coil is energized, a
magnetic field develops and causes the armature to urge the tappet
against the valve seat in overcoming the resistance of the
resetting spring. Thus, the prior art magnetic valve is illustrated
as a normally open valve, called NO valve in short.
The top housing part in this valve is made of a non-ferromagnetic
material in order to prevent a magnetic short-circuit and permit
operation of the valve with small losses only. This aspect is of
special significance when, as is the case in anti-lock systems
(ABS) or traction slip control systems (TCS) in automotive
vehicles, there is the requirement of high closing pressures, on
the one hand, and small overall dimensions, on the other hand. It
is a general objective in these and other cases of application to
minimize the magnetic losses to the greatest possible extent in
order to achieve a compromise between contrasting requirements
which is also reasonable under economical aspects.
Because the armature must be movable axially for functional
reasons, a radial air gap is exactly as necessary as an axial
residual air gap between the magnetic core and the armature in
order to avoid a sticking connection. Also, the wall thickness of
the top housing part which is not ferromagnetic must be considered
as a loss-involving 'air gap'. More specifically, the magnetic
losses which are produced by the sum of the air gaps in the prior
art magnetic valve adopt a value which cannot be reduced any
further, not even if highly narrow manufacturing tolerances are
complied with.
The prior art magnetic valve suffers from the additional
shortcoming that its adjustability is very intricate. During the
assembly, a thin washer which corresponds to the residual air gap
desired is interposed between the armature and the magnetic core.
Thereafter, the top housing part with its contents is inserted into
the bottom housing part until the magnetic core bears against the
bottom housing part in an axial direction. The tappet which is
initially inserted into the armature only in a light press fit and
is supported on the valve seat is displaced upwardly relative to
the armature. Subsequently, the parts are dismantled again, and the
tappet is fixed in position in the armature by caulking.
In the second adjustment step, a washer which corresponds to the
desired air gap in the deenergized condition, hence, which
corresponds to the residual air gap plus working stroke desired is
inserted between the armature and the magnetic core. All parts are
assembled again, and the top housing part is urged into the bottom
housing part until the magnetic core bears against the stop. In
this arrangement, the armature is shortened plastically in its top
weakened area by the size desired. Thereafter, the assembly must be
dismantled and the washer removed before the parts can be
reassembled and, as described hereinabove, coupled to each other in
a third step.
The generic German utility model application No. 8522724.2
discloses a magnetic valve which includes a first cylindrical
housing part, made of a ferromagnetic material, to form the
magnetic core, and a second sleeve-type housing part, made of a
ferromagnetic material, to accommodate a magnetic armature and a
valve seat member which has a plurality of pressure fluid ports
that are separated hydraulically by a tappet fitted to the magnetic
armature in the initial position of the valve. Another housing
portion which is made of a non-magnetic material is provided
between the two housing parts. The above-mentioned separate housing
parts are joined in the area of the non-magnetic material.
An object of the present invention is to improve upon a magnetic
valve of the type mentioned hereinabove so that the magnetic losses
in the working range of the valve can be reduced further, on the
one hand, and that the valve adjustment can be simplified, on the
other hand.
Surprisingly, it has shown that the losses due to magnetic
short-circuits are reduced when conventional ferromagnetic
automatic steel is used compared to a magnetic valve of the prior
art type which is comparable in its overall size. This is due to
the fact that, on the one hand, at least the losses caused by the
radial air gap can be reduced and, on the other hand, magnetic
saturation occurs very quickly in the area of the sleeve due to the
small wall thickness. Even at operating pressures of 200 to 350 bar
and in consideration of usual safety margins, the load-bearing
sleeve cross-section can be reduced so that the short-circuit
losses in the one-part housing are lower than in the prior art
two-part housing with a top sleeve-type part made of a
non-ferromagnetic material. Besides, material selection and a
specific heat treatment offer further possibilities to shift the
necessary compromise in designing the sleeve cross-section so that
the magnetic short-circuit losses are further reduced.
Another advantage of the one-part housing design is that it
obviates the need for adapting and joining steps and that it
reduces the number of manufacturing tolerances to be considered.
This becomes apparent especially in the adjustment of the magnetic
valve, wherein due to the large number of parts cooperating in
magnetic valves for an operating pressure of e.g. 200 to 220 bar,
the operating pressure may vary between 200 and 350 bar without
adjustment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-sectional view of a first embodiment of
a magnetic valve of the present invention.
FIG. 2 is a view of a second embodiment.
FIG. 3 is a variation of the second embodiment.
FIG. 4 is another variation of the second embodiment.
FIG. 5 is a variation of the first embodiment.
FIG. 6 is a view of a third embodiment.
FIG. 7 is a view of a fourth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiment of FIG. 1, the top housing part 1 of the one-part
housing is made of a solid cylindrical portion 6 which is
encompassed by a magnetic coil 35, and a downwardly following
sleeve 4 which is connected integrally with the bottom housing part
2 configured as a screw-type coupling part. The sleeve 4 defines an
interior bore 3a. The bore 3a and the top area of the top housing
part 1 are used to axially guide the armature 3 which is supported,
on the one hand, on a resetting spring 21 that acts in the closing
direction and an anti-stick washer 22 in the solid cylindrical
portion and, on the other hand, on the tappet 8 which in turn bears
against the valve seat 7. The bottom housing part 2 has a central
bore 5 which is slightly larger than the armature bore 3a, and the
step in diameter created by the interface of the two bores provides
an annular housing stop 4a which can be used as plane of reference,
as will be explained hereinbelow. A tubular support member 6 is
inserted into the bore 5 which, beside the valve seat 7, includes
an insert 15 and a washer 16 which are used to guide the tappet 8.
The insert 15 and the washer 16 are both formed in the nature of
annular metal washers, each having axial passages 17 and
18,respectively, extending through their annular bodies. Ideally,
in the embodiments of FIGS. 1-3, the thickness of the insert 15
will be greater than that of the washer 16. The insert 15 is
pressed into the support member 6 and welded at its edge, if
necessary, and the washer 16 is retained in the support member 6 by
way of a caulked ring (not referred to). The interior of the
support member 6 is subdivided by the valve seat 7 into a top
inside space 9 and a bottom inside space 12 which are connected to
outside valve ports 11, 14 by way of a radial respectively axial
bore 10, 13. Beside the central bore 5 to guide the tappet 8, the
insert 15 and the washer 16 each have at least one passage 17, 18
for the conveyance of working fluid medium. The tappet 8 is
equipped with a thrust 19 on which a resetting spring 20 that acts
in the opening direction is supported, and the other thrust of
spring 20 is defined by the washer 16. The thrust 19 is defined by
a boss extending circumferentially about the tappet 8.
For the stroke adjustment, it is deterimined, on the one hand, how
far the tappet 8 which is preassembled in the support member 6,
with the resetting spring 20 compressed and with a support on the
valve seat 7, projects from the upper boundary plane of the insert
15, mounted flush with the support member 6. The upper extremity 6a
of the support member 6 will remain in contact with the annular
housing stop 4a at all times. On the other hand, it is determined
how far the armature 3 is set back compared to the plane of
reference produced in the housing due to the step in diameter, with
the resetting spring 21 compressed and abutment of the armature 3
on the top housing part without anti-stick washer. The thickness of
the necessary anti-stick washer 22 is then calculated from both
measurements.
Reference numerals are used in the following Figures only inasfar
as they are required to explain the differences over the previously
described embodiments. Details which have not been modified or
which are per se obvious will not be referred to for the sake of
clarity. The same applies especially to the illustrated peripheral
components, such as seals, end caps and filters, which are
customary in magnetic valves of this type and well known to the
expert in the art.
In the embodiment of FIG. 2, the top housing part 1 has a central
bore 23 which is expediently stepped and used to accommodate the
resetting spring 21 and a cylindrical thrust 24. The bottom housing
part 2 with valve seat 7 and tappet 8 is not modified compared to
the FIG. 1 embodiment. The armature 3 which, with part of its
length, is guided in the sleeve 4 of the housing 1, 2 is supported
on the valve seat 7 by way of tappet 8 and on the resetting spring
21 by way of an anti-stick washer 22. Resetting spring 21, in turn,
is supported on the ball 25 that is sealingly pressed into the bore
23 by way of the thrust 24. To adjust the desired closing pressure,
the ball is pressed in downwardly, when installed into the bore 23,
as far as until the bias of the resetting spring 21 on the valve
seat 3 produces the desired closing pressure, and the latter
pressure is applied from below through the valve seat either
mechanically or hydraulically to the tappet 8. More specifically,
the ball 25 is slipped in until the valve seat 7, with the
application of opening pressure, is closed by the tappet 8.
The embodiment according to FIG. 3 differs from the embodiment of
FIG. 2 in that the ball 25' in the bore 23' has only a sealing
function rather than an adjusting function. The hollow-cylindrical
thrust 24' which is undisplaceably inserted into the housing part 1
serves as a top support for the resetting sprng 21, and the bottom
support occurs by way of the anti-stick washer 22 on the armature
3' which includes a central guide pin 28. On the opposite side, the
armature 3' has a plastically defonnable bead 29. The housing part
2 again has a stop 30, and both housing parts 1, 2 are integrally
interconnected by way of a sleeve 4.
To explain the adjustment, the support member 6 with the components
it comprises is once more illustrated in detail in the embodiment
of FIG. 3a. The tappet 8 bears against the valve seat 7 and is
guided by way of the insert 15' and the washer 16'. Washer 16' is
retained in the support member 6 by a clamping ring 16a. In the
preassembly, the insert 15' is slipped into the support member 6
until its top boundary plane 26 is flush with the stop surface 27
of the tappet 8 which abuts the valve seat 7, with the resetting
spring 20 compressed. The insert 15' is fixed in this position in
the support member 6. Subsequently, the armature 3' is pushed
upwardly until it reaches the stop and the bead 29 is deformed
plastically until its stop surface is set back by the desired
operating stroke compared to the stop 30 in the second housing part
2.
The embodiment of FIG. 4 shows a variation of the FIG. 3
embodiment. Only FIG. 4a will be explained more closely. Instead of
the insert 15' and the waher 16', only a washer-type insert 31 with
an extended guide portion 32 is provided to guide the tappet 8. The
support member 6 is plastically deformable at its top end due to
the provision of recesses in the cylindrical edge and the remaining
edge portions tapering. It is ensured in the preassembly that the
top area 33 of the support member 6 is urged to retreat by
plastical deformation so far that its stop plane is flush with that
one of the tappet 8 which then abuts on the valve seat. The further
adjustment on the armature 3' is effected as in FIG. 3.
FIG. 5 shows an embodiment wherein exactly as in FIG. 1 the top
housing part 1 is configured as a solid cylindrical area. In
contrast to FIG. 1, however, the tappet 8' is not configured as a
component part which is movable irrespective of the armature 3" but
retained in the armature. This obviates the need for the second
resetting spring 20 because the tappet 8' automatically follows the
movements of the armature 3". The insert 15 to guide the tappet 8'
was also omitted. Washer 16' is still provided which is fixed in
position in the support member 6' by a caulking ring (not shown).
The plastical deforinability of the top area 33 of the support
member 6' was taken from the embodiment of FIG. 4.
For the adjustment, the armature 3" with the tappet 8' retained in
a light press fit is inserted into the housing and pushed upwardly
until the stop is reached. Subsequently, the tappet 8' is pushed
upwardly relative to the armature 3" until the stop surface 27' of
the tappet 8' is at a predetermined axial distance from the stop 30
in the housing part 2. Further, the deformable area 33 is
compressed downwardly until its stop plane is at a defined distance
from the valve seat 7. Thereafter, the support member 6 can be
slipped into the bottom housing part 2 until stop 30, with the
result that the desired operating stroke is adjusted.
In the embodiment of FIG. 6, the housing 1,2 includes a stopped
bore 36 whose top portion 37 has the smallest diameter and is
closed by a plastically deformable housing wall portion 38 which is
designed integrally with the housing 1,2. A pin 39 is arranged in
this portion 37. In the mid-portion 40, the axially slidable
armature 3" with the attached tappet 8" is arranged, as well as a
magnetic core 41 with a guide bore for the tappet 8". A resetting
spring 42 which acts in he opening direction is compressed between
the armature 3" and the magnetic core 41. A valve seat 44 is
pressed into the bottom portion 43 of the stepped boe 36 which has
the largest diameter.
FIG. 6 depicts a variation showing what a customary NO-valve would
look like based on the above suggestions. The position of the
sealing ball of the tappet 8" is dictated by the bead 30' and is
adjusted by deformation of the area 38 and the related movement of
the pin 39 which has previously been pressed in. Tappet 8" and
armature 3" are rigidly connected.
To position the magnetic core 41, the armature 3" is pressed in so
as to be roughly preposition. The press-in accommodation comprises
a coil which is thn energized. This causes the air gap to close,
and the tappet 8" and said's sealing ball 27' change their position
with respect to the bead 30'. Continued pressing in of the magnetic
core 41 causes the armature 3" with the tappet 8" to adopt the
optimal position with respect to the bead 30'.
In the embodiment of FIG. 7, the top portion of the top housing
part 1 again has a solid cylindrical design. The stepped bore 46
houses the armature 3", the anti-stick washer 22, the resetting
spring 42', the magnetic core 41' and the tappet 8". A valve seat
44 is pressed into the bottom part 48 of the stepped bore until the
stop 30' is reached.
The tappet 8" is prepositioned in the armature 3" only in a light
fit in this case. Both parts are fitted into the housing 1,2, and
then the tappet 8" is displaced upwardly relative to the armature
3" until the stop surface 27' of the tappet 8" again has a
predetermined axial distance from the stop 30', preferably, until
it is flush with the stop 30'. Thereupon the magnetic core 41' is
slipped in until its bottom edge is at the predetermined axial
distance from the reference plane defined by the stop 30' or until
the resetting sprin 42' has a predetermined bias which can be
checked by retraction of the tappet 8". This permits adjusting the
desired air gap between the armature 3" and the magnetic core 41'
when the magnetic coil is not energized.
FIG. 7 depicts a variation of FIG. 6 in the positioning of the
sealing ball 27' relative to the bead 30' by displacing the tappet
8" in the armature 3" which is supported on a washer 47. A further
considerable increase in force can be achieved by a washer 22 which
is disposed at the air gap and associated with the magnetic core
41.
The above-mentioned embodiments and possible adjustments permit
adapting the one-part housing of the present invention to most
various requirements. More particularly, normally open and normally
closed valves can be achieved, as has been shown. The adding
manufacturing tolerances may be adjusted in the assembly in all
cases. The manufacture of the housing is less costly than that of
multi-part housings. It necessitates reduced assembly efforts, and
a magnetic valve comprising a housing of this type is very easily
adjustable.
The above-mentioned adjustment possibilities may of course also be
used--directly or in a modified form--in other shapes of housings,
especially in housings made up of two or more parts, provided
similar installation conditions prevail. Under certain
circumstances, the same advantages as in the one-part housing of
the present invention may be achieved.
* * * * *